Tunnel barker



March 12, 1963 A. P. SCHNYDER TUNNEL BARKER 5 Sheets-Sheet 1 Filed April 22, 1960 INVENTOR .zilazilzlus ficknyder BY 1 AGENT Max ch 12, 1963 A. SCHNYDER TUNNEL BARKER 5 Sheets-Sheet 2 Filed April 22. 1960 IIIIIIIII IIIIIII LP March 12, 1963 A. i SCHNYDER TUNNEL BARKER 5 Sheets-Sheet 3 Filed April 22, 19 60 INVENTOR I? .fclzlzydr .zazjlg 'gs' ax/6*. AGENT United States atent I estates Patented Mar. 12, 1963 fiice barking drum which is capable of quickly and cheaply removing the bark from pulpwood. The barking drum which consists essentially of a large rotating drum removes the bark from pulpwood by friction primarily through the tumbling action of the pulpwood logs as they pass through the drum. As a result of the somewhat violent and random tumbling action occurring within the drum, the ends of the pulpwood logs become broomed by the time the logs are discharged from the drum. Brooming during barking accounts for a 4 to 5 percent loss of wood fibers and has a deleterious effect on the quality of the paper if any particles of sand or dirt are present in the barking drum, since such particles are pounded into the broomed ends and are subsequently 'carried through the deligniiication and paper making processing steps. In order to reduce the quantity of sand and dirt and to improve the quality of the paper product, it is therefore sometimes necessary to remove the broomed ends prior to delignification which results in an additional loss of wood fibers per unit of untreated pulpwood.

The present invention provides an eifective and efficient means for barking pulpwood while eliminating the disadvantages resulting from the apparatus heretofore utilized wherein barking is accomplished by means of the friction created by the tumbling and rotating action of the pulpwood logs. Further, the present invention is capable of barking a substantially greater quantity of pulpwood as compared to a barking drum of like size at reduced operational costs and maintenance.

It is a principal object of this invention to provide an improved barking apparatus for removing bark from pulpwood.

' Another object of my invention is to provide an improved barking apparatus whereby brooming of the pulpwood is substantially eliminated.

A further object of my invention is to provide an improved barking apparatus which substantially reduces fiber losses during barking While increasing by 25 to 50 percent the barking capacity for an apparatus of like size as compared to a conventional barking drum.

Still another object of this invention is to provide an improved barking apparatus having a construction providing unique orientation of logs during their handling in the apparatus.

A further object of this invention is to provide an improved barking apparatus which may be continuously operated and into which logs can be fed at a uniform rate, the logs being debarked and automatically fed to and discharged from the apparatus.

Still another object of this invention is to provide an improved barker of the aforementioned type permitting the use of steam during the barking operation to aid in the removal of bark, which apparatus has a minimum of loss of steam during continuous insertion and removal of logs with respect to the barker.

Still another object of this invention is to provide an improved barker of the aforementioned type which has a rock-like massiveness which is especially suited for the task of barking hardwood logs of large size and weight.

To achieve the aforementioned and other objects of this invention, the present barking apparatus, hereinafter referred to as a tunnel barker, may be comprised of a keyhole-shaped tunnel structure designed to accommodate a rotating scroll cage for moving a stack of generally parallel logs transversely and upwardly along one side of the tunnel whereby the logs roll and cascade about each other for removal of the bark. The tunnel is of a generally cylindrical shape and the cage includes a plurality of angularly spaced pusher elements extending generally longitudinally of the tunnel and having a triangular cross-section. The pusher elements are rigidly and uniformally connected to a plurality of rings which rotatably support and drive the cage structure. A mechanical drive for the cage may be achieved by at least one driven pinion intermeshed with a gear tooth structure aflixed upon one or more of the rings of the cage. Some of these rings may be so constructed as to define part of the periphery of said tunnel, whereas the axially adjacent parts of the inner periphery of the tunnel are defined by stationary concrete structures. At the bottom of the circularly or cylindrically shaped portion of the tunnel there is provided a grillage assembly shaped to the radius or curvature of the tunnel and formed of substantially parallel curved bars. The grillage assembly permits the withdrawal from the tunnel of the bark removed from the logs passing therethrough. The removed bark drops through the grillage and is thereafter guided by a chutelike structure onto a bark transfer conveyor provided beneath the chute-like structure. Steam generating or injecting means may be provided at the periphery of said tunnel to subject the logs being barked to heat and moisture to assist in removing the bark.

In operation, the pulpwood logs are continuously fed into the tunnel barker over a battery of overspeed rolls which impart to the logs a ballistic like trajectory as they enter the tunnel. The logs are forced to align axially in the tunnel by the pusher elements of the scroll cage which sweep the tunnel over its full length and force the logs to cluster in a semi-circular formation along an inclined plane. This action causes the logs to rotate within the semi-circular formation as well as cascade from the crest to the toe of the inclined plane. The pusher elements, as a result of their triangular shape, heave the logs and therefore add to the total barking action. Barking is primarily effected by the friction created by the rotation of the logs within the inclined plane thereby differing from the primary barking action of the conventional barking drum. Since barking is primarily effected by the rotational action of the pulpwood logs, brooming of the log ends is substantially eliminated.

The grillage assembly mounted on the bottom arc of the tunnel permits the bark loosened during the forward movement of the logs through the tunnel to drop to the bark transfer conveyor located below the grillage assembly. The movement of the logs through the tunnel is pseudo-hydraulic, i.e., after initial loading, for every log introduced into the barker, one is essentially simultaneously discharged. The rate at which the logs are fed into the barker is a function of the type of wood for a predetermined speed in revolutions per minute of the scroll cage. The discharge end of the tunnel barker is essentially open and has a discharge apron to permit efiicient removal of the debarked pulpwood logs which are there- 0 after processed for digester feed stock.

tailed description which is given merely by way of exampie of a preferred embodiment of the present invention, but which is not to be taken as limiting except as the invention is defined in the appended claims, the description referring to the drawings wherein:

FtGURE 1 is a vertical sectional view of the tunnel barker for removing bark from pulpwood taken on line 11 of FIGURE 2.

FlGURE 2 is a partial elevational view of the tunnel barker with a portion broken away to illustrate the internal structure of the barker.

FIGURE 3 is a feed end view of the tunnel barker shown in FIGURE 1.

FIGURE 4 is a sectional view of the grillage assembly of the tunnel barker taken on line 4-4 of FlGURE 2.

FIGURE 5 is a sectional view of a pusher element of the scroll cage taken on line 55 of FIGURE 2.

Having hereinabove generally described the nature of the invention, now referring to the drawings wherein like reference numerals indicate like parts throughout, there is provided a tunnel barker, generally designated at 10, functioning to remove the bark from pulpwood logs, and

comprised of a cast-in place keyhole-shaped concrete structure 11 mounted on a sturdy floor or base 12.

The barker It) is comprised of a horizontally crosswise split circularly cylindrical upper wall 13 supported integrally with lower base stand 14. As illustrated in FIGURE 2, the upper wall 13 is longitudinally discontinuous due to its formation with slots 15 to provide for supporting trunnion and drive assemblies for a rotatable scroll cage or cage-like structure 16 as described in detail hereinafter. The upper portion of the barker 10 is formed with a centrally located cylindrical tunnel space 17 as determined by the inner surface 18 of the wall 13 and a grillage or grill-like structure 19 which separates removed bark from the logs. The inner surface 18 of the wall-13 joins the sides of the grillage 19 along vertical surfaces 29a and 20b of base stand 14, which depending surfaces form with converging and vertically inclined surfaces 21a and 21b of the base stand 14, bark removal chute 22. The logs are supported or stacked during rotation of the cage 16 generally parallel to each other at the bottom of and upwardly along that side of space 17 at that portion of cage 16 which is upwardly moving.

The feed end 23 of the barker 1G is enclosed by a feed end wall 24 extending from the top of the wall 13 to the bottom of the chute 22. The end wall 24 has a feed inlet portal 25, for introducing the logs to be debarked into the barker 10, in an upper quadrant or sector of the circular portion of the end wall, offset to one side and above the longitudinal center line of tunnel 17 as illustrated in FIGURE 3. Between the surfaces 20a and 20b of base stand 14 and formed on the inner portion of end wall 24, there is provided an arc-shaped flange 26 shaped to the radius of the tunnel 17. The discharge end 27 of the barker 10 is open to permit the free discharge of barked pulpwood logs. At the discharge end of the barker the bark removal chute 22 is enclosed by end wall 28 which is similarly provided on the inner surface thereof with an arc-shaped flange 29 shaped to the radius of the tunnel 17. Set within the wall 13 and flanges 26 and 29 are metal end rings 30 and 31, respectively. At the discharge end 27 of the barker 10 and forming a longitudinally extending part of the structure 11 is a discharge apron 32 which extends from the top of the tunnel 17 around through 180 at the side of the tunnel 17 nearest the viewer in FIGURE 2, and thence horizontally away from the viewer to outer surface 33 (FIGURE 3) of the base stand 14.

Below the bark chute 22 and extending generally parallel to the tunnel 17 is a bark transfer conveyor passage 34 defined in part by the channels 34:: and 34b, which channels in turn are defined in the base 14 by generally vertically and inwardly extending channel walls 35a and 3%, the parallel innermost edges of which define the -e,oso,sas

inbefore-mentioned rollers 49. ,the end-stiffener rings 43 and 44, is smaller than the cir- 4 outlet of chute 22, and horizontally extending ledges or supports 36a and 36b which may be utilized for supporting a conventional conveyor belt apparatus 37. The belt conveyor 37 is comprised of idler support members 38a and 381) which include suitable bearings for carrying idler rollers 39 supporting a conveyor belt 40, the latter being of such width as to extend at each edge beneath and parallel to the innermost edges of walls a and 35b. Any suitable drive means may be utilized to operate the conveyor belt. By removing the conveyor structure shown in FIGURE 1 in the conveyor passage 34, the latter may be provided with a liquid stream flowing therethrough and serving as a flume to remove the bark dropping through the grillage 19 and chute 22.

The grillage 19 may be arranged as seen in FIGURE 1 to formthe lower portion of the tunnel 17 and is comprised of arcuately curved bars 41 conforming to the cylindrical configuration of the tunnel 17 .and of substantially the same radius as the interior'surface 18. The ends of the bars 41 may be supported in the wall 13 of the concrete structure and these ends as well as the intermediate portions of the bars may also be supported in fixed relationship to each other by reinforcing rod mem- 'bers'41a or the like extending longitudinally of the tunnel 17 and passing through and/or being secured to the bars, as by welding, both the bars and the reinforcing rods 41a being of metal. The grillage 19' may be comprised of a structure extending over substantially the entire length of the tunnel 17 (except for the slots 15) and may be made up of a plurality of sections extending end to end or with portions of the concrete structure having a configuration generally similar to the arcuate portions 26 and 29 extending between the adjacent grillage parts. The bars 41 of the grill structure 19 may be inclined orpitched with respect to a vertical plane extending transversely of the axis of tunnel 17 to impart some forward movement to the cluster or stack of logs which may be partially supported by the grillage 19'. Movement of the logs along the surface of the grillage 19 by means of the rotatable cage 16 effects this forward movement.

The configuration of wall 24 will permit entry of the logs at the respective inlet end of the tunnel but will preclude any axial movement of the logs toward the right as seen in FIGURE 2 and at least partially for this reason the pulpwood logs will pass through the barker toward the left ina pseudo-hydraulic manner, the pitching of the grillage bars 41 giving an assist to the movement of the logs through the barker.

The scroll cage, generally indicated as '16, is constructed of pusher elements 42 of triangularly shaped cross-section rigidly mounted to end stiffener rings 43 and 44, and intermediate mounting rings 43a and 4411. Referring to FIGURE 5, which illustrates the details of construction of the triangularly shaped pusher element and the manner in which it is mounted to end stiffener ring 43, the pusher element 42 is comprised of a steel plate 45 and flat plate 46 which define its triangular crosssection and are welded to each other and to end stiffener ring 43. The triangularly shaped pusher elements 42 are similarly mounted to end stifiener ring .4 and mounting rings 43a and 44a.

Referring further to FIGURE 5, the end stiffener rings 43 and 44 may be provided with roller asemblies generally indicated at 47 around the circumference of the rings and at the points at which the triangularly shaped pusher elements are welded thereto. The flat plate 46 of the pusher elements, and end stiffener rings 43 and 44 are provided with openings 48 which permit the roller 49 of the roller assembly 47 to extend beyond the outer circumferential surface of the end stiffener rings 43 and 44. The roller assembly 47 is comprised of shaft supports 50 welded to plate 46, roller shafts 51 and the here- The outer diameter of cumference of the tunnel 17 so that in operation the rollers 49 extending through the apertured end stiffener rings ride on stationary rings 30 and 31 mounted at least in part in arcuate flanges 26 and 29, respectively.

Rigidly affixed as by welding to the outer surface of the metal mounting rings 43a and 44a, there are provided respective trunnion bearing rings 51 and 52, and driven gears 53a and 53b. The bearing rings 51 and 52 are supported by externally mounted pairs of trunnion rollers 54 and 55, respectively. The trunnion rollers 54 and 55 are each supported from trunnion mountings 56 and a shaft '57, the trunnion mountings 56'being carried by supporting parts 58 of the structure 11 at the base of slots 15. The drive mechanism comprises a line shaft 59 having pinion gears 60a and 6% which engage the driven gears 53a and 53b of the scroll cage 16. The line shaft is rotatably mounted in bearing blocks 61 carried by supporting parts 62 of structure 11 and may be driven by any suitable means (not shown) such as a short center belt from a high torque, multi-speed motor. The purpose of the multispeed motor having two or more speeds is to provide a means by which the barking action of the barker 10 may be adjusted to various wood species and to account for seasonably changing barking conditions.

In order to provide steaming of the logs within the tunnel 17 during use of the barker, steam generating or injecting nozzles or the like may be provided at the sides and/ or end of the tunnel, preferably where they will not be obstructed or engaged by the logs, and the inlet and outlet openings of the tunnel housing may be provided with any suitable steam retaining or blocking means such as curtains to permit the entry and discharge of logs while at the same time providing an effective retainer for the steam within the tunnel 17. I

In addition to the description of the operation of the invention immediately preceding the detailed description of the illustrated apparatus, it might be pointed out that the logs may be pulled away from the rotating or cascading clusters at the discharge end of the tunnel by overspeed rollers and thereafter the logs may be transferred horizontally to a follow-up discharge conveyor of any suitable structure (not shown).

It is to be noted that the use of the steaming during or prior to the barking steps facilitates the removal of bark, particularly from hardwood.

Not only is the concrete structure 11 of very great weight and size but also the other structural parts of the barking apparatus are made sufliciently sturdy to provide a massiveness and strength of the barking apparatus especially suited for the task of hardwood barking and the construction according to this invention not only improves the barking action substantially but also is such as to provide a simple and economical structure having a reduction in wear and tear and operating and maintenance expenses incomparable with known barking structures.

In the operation of the barker the rate of feed of logs into and the rate of discharge of logs from the barker may preferably be such that roughly one half of the tunnel space is filled with logs and the rate of rotation of the barker may be such that the slope of the log cascade may be approximately 45 with respect to the horizontal whence the logs will cascade from the top to the toe of the slope.

The diameter of the tunnel 17 may be approximately 12 feet for barking of logs which average about 8 inches in diameter, but may range from 3 /2 to 24 inches, and are of a length averaging about 5.3 feet, but ranging between and feet. The length of the tunnel is selected to provide the desired bark removal by the time the logs are automatically discharged therefrom and a suitable length for the above conditions may be about 48 to 72 feet.

The cage structure 16 may be provided with suitable wiping means to prevent the deposition of removed bark on the inner surface of the wall defining the tunnel 17.

6 Also, a slight inclination of the axis of the tunnel may aid in the progression of the logs therethrough.

Because of the nature of the barking action of the present invention, the bark will break up into reasonably small particles and should fall through the grillage 19 and accordingly, the necessity for a bark hog to reduce the size of theremoved bark is obviated.

While there is shown and described a preferred embodiment of this invention, it is obvious that other variations may be made, and therefore, it is intended that this description be not limiting of the scope of the disclosure except as the invention is defined herein in the following claims.

I claim:

11. An apparatus for removing bark from pulp wood logs comprising an elongated rotatable cage-like structure having an open inlet and an open outlet end, said cage-like structure comprising two or more ring means spaced axially of each other, a plurality of longitudinal. members secured to both said ring means, a housing for at least partially enclosing said cage-like structure and including means for supporting the latter for rotation about a generally horizontal axis, said cage-like structure having an internal space adapted to accommodate a plurality of pulp wood logs stacked with their axesgenerally parallel to the rotational axis of said cage-like structure, said longitudinal members being sufiiciently spaced such that a substantial portion of said logs are supported directly by said housing means in engagement with one or more of said ring means for rotating said cage-like structure to cause said logs to roll within said housing and upon one another to remove the bark therefrom, means beneath said cage-like structure by which the removed bark is discharged, and means for causing logs within said apparatus to move progressively from the inlet end to the outlet end thereof during rotation of said cage-like structure.

2. Apparatus according to claim 1, wherein the means beneath said cage-like structure for discharging the removed =bark comprises a grill-like structure which is engageable with at least some of said logs during rotation of said cage-like structure.

3. Apparatus according to claim 1, wherein said axially spaced ring means includes at each end thereof a reinforcing ring connected to each of said longitudinal members.

4. Apparatus according to claim 3, wherein the support means for the cage-like structure includes at each reinforcing ring a plurality of rollers for rotatably supporting said cage-like structure on said housing.

5. Apparatus according to claim 4, wherein said rollers are carried by said cage-like structure and further including a track structure on said housing upon which said rollers roll.

6. Apparatus according to claim 5, wherein said rollers are mounted at the ends of and at least partially within respective longitudinal members of said cage-like structure.

7. Apparatus for removing bark from pulp Wood logs comprising a stationary structure enclosing an elongated tunnel space and including structural parts at least at the bottom and at one side of said space adapted to support a plurality of logs lying directly on said stationary structure, stacked upon each other with their lengths extending generally longitudinally of said space, rotatable means for engaging and moving said log-s from the bottom of} said space transversely and upwardly toward said one side to cause said logs to roll upon each other in said space for removing the bark therefrom, said rotatable means including two or more ring means spaced axially of each other, a plurality of longitudinal members secured to both said ring means, said longitudinal members being sufliiciently spaced such that a substantial portion of said logs are supported directly by said stationary structure, means in engagement with one or more of said ring means for causing ratotion of said rotatable means, said structure having openings at opposite ends to provide entry and discharge, respectively, of logs with respect tosaid tunnel space.

8. Appartaus according to claim 7, wherein said space is generally cylindrical and wherein one of said structural parts is a grate-like portion at the bottom thereof to permit discharge of the removed bark from said space.

9. Apparatus according to claim 7, wherein said stationary structure includes at the inlet end, where logs enter the tunnel space, a wall extending transversely of said .tunnel space and partially closing the latter at least over of the removed bark from said space including a grill structure having a plurality of arcuately-shaped bars extending generally trnasversely of the longitudinal direction of said space.

11. Apparatus according to claim 10, wherein said bars are inclined to planes transversely of the length of said tunnel space for urging said logs to move progressively from an inlet and to an outlet of said space as they are rolled upon each other in said space.

12. Apparatus for removing bark from pulp wood logs comprising a stationary structure enclosing an elongated tunnel space having a generally cylindrical periphery, rotatable means for transversely moving and lifting at least a part of a plurality of logs adapted to be stacked within said space with their lengths extending generally longitudinally of said; space to cause them toroll and cascade upon each other for removing bark from said logs, said rotatable means including a pair 015 ring members spaced axially of each other, a plurality of longitudinal members se ured to both said ring members, means in engagement with both said ring members for causing rotation of said rotatable means, said stationary structure being provided with means at the bottom thereof for separating removed bark from the logs in said space, and means extending longitudinally of said space and beneath said separating means for collecting the separated bark.

13. Apparatus according to claim 12, wherein said collecting means is a chute-like structure having an elongated outlet therebeneath generally parallel to said elongated space.

14. Apparatus according to claim 13, including means beneath said outlet for conveying the removed bark away from said outlet.

15. Apparatus according to claim 14, wherein the conveying means for removing the bark from said outlet is a belt conveyor.

16. Apparatus according to claim 13, wherein said chute-like structure includes a passage below said outlet and a belt conveyor in said passage, said belt conveyor in luding a belt having an upwardly exposed conveying surface beneath said outlet, said chute-like structure having portions defining the edges of said outlet, which portions overlie and extend generally parallel to the edges of said belt.

17. Apparatus according to claim 12, wherein said longitudinal members are each triangular in cross-section.

18. Apparatus according to claim 1 wherein said longitudinal members are trinagular in cross-section.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,080,898 March 12, 1963 Auxilius Peter Schnyder It is hereby certified that error appears in the above numbered pat ent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 27, after "housing" insert a comma.

Signed and sealed this 31st day of December 1963.

SEAL) I ttest: EDWIN Lo REYNOLDS ERNEST W. 'SWIDER A v Attesting Officer Acting Commissioner of Patents 

1. AN APPARATUS FOR REMOVING BARK FROM PULP WOOD LOGS COMPRISING AN ELONGATED ROTATABLE CAGE-LIKE STRUCTURE STRUCTURE COMPRISING TWO OR MORE RING MEANS SPACED AXIALLY OF EACH OTHER, A PLURALITY OF LONGITUDINAL MEMBERS SECURED TO BOTH SAID RING MEANS, A HOUSING FOR AT LEAST PARTIALLY ENCLOSING SAID CAGE-LIKE STRUCTURE AND INCLUDING MEANS FOR SUPPORTING THE LATTER FOR ROTATION ABOUT A GENERALLY HORIZONTAL AXIS, SAID CAGE-LIKE STRUCTURE HAVING AN INTERNAL SPACE ADAPTED TO ACCOMMODATE A PLURALITY OF PULP WOOD LOGS STACKED WITH THEIR AXES GENERALLY PARALLEL TO THE ROTATIONAL AXIS OF SAID CAGE-LIKE STRUCTURE, SAID LONGITUDINAL MEMBERS BEING SUFFICIENTLY SPACED SUCH THAT A SUBSTANTIAL PORTION OF SAID LOGS ARE SUPPORTED DIRECTLY BY SAID HOUSING MEANS IN ENGAGEMENT WITH ONE OR MORE OF SAID RING MEANS FOR ROTATING SAID CAGE-LIKE STRUCTURE TO CAUSE SAID LOGS TO ROLL WITHIN SAID HOUSING AND UPON ONE ANOTHER TO REMOVE THE BARK THEREFROM, MEANS BENEATH SAID CAGE-LIKE STRUCTURE BY WHICH THE REMOVED BARK IS DISCHARGED, AND MEANS FOR CAUSING LOGS WITHIN SAID APPARATUS TO MOVE PROGRESSIVELY FROM THE INLET END TO THE OUTLET END THEREOF DURING ROTATION OF SAID CAGE-LIKE STRUCTURE. 